Quasi-Phase-Matched Faraday Rotation in Semiconductor Waveguides With a Magnetooptic Cladding for Monolithically Integrated Optical Isolators

Strategies are developed for obtaining nonreciprocal polarization mode conversion, also known as Faraday rotation, in waveguides in a format consistent with silicon-on-insulator or III-V semiconductor photonic integrated circuits. Fabrication techniques are developed using liftoff lithography and sputtering to obtain garnet segments as upper claddings, which have an evanescent wave interaction with the guided light. A mode solver approach is used to determine the modal Stokes parameters for such structures, and design considerations indicate that quasi-phase-matched Faraday rotation for optical isolator applications could be obtained with devices on the millimeter length scale.